Menu Menu

All you Wanted to Know about The Phases of Clinical Trials

Clinical trials are conducted to evaluate the safety and efficacy of new drugs, biologics, or medical devices. Before the study is undertaken on human subjects, it is tested in laboratories and on animals. If the investigational product is found safe and efficacious in the preclinical testing, it is further approved for studies on human subjects in order to have its market approval.

We bring you a breakdown of the 5 commonly referred phases of clinical trials:

Phase 0 – Also known as human micro dosing, in this phase drug is given to about 10 to 15 healthy volunteers to check the safety of the drug. Then these patients are closely monitored to check if the results are as expected.

In most cases, the dose is extremely low to be therapeutic, but it is mainly designed to test the tolerability of the drug on human bodies.

Phase I – The investigational drug is then tested on around 20-100 healthy or diseased individuals in order to check both safety and efficacy of the drug. Phase I trials can have multiple designs like single ascending dose studies, multiple ascending dose studies and food effect studies. The varying quantity of the doses and their effectiveness with or without food is usually tested at this stage.

Phase II – Once the safety of the drug is tested in Phase 0 and I, the phase II trials begin. In this phase, the number of patients is usually higher ranging between 100 to 300. Both safety and the efficacy of the investigational product is evaluated. In Phase IIa, researchers evaluate the most effective quantity of the dose while in Phase IIb, studies show how effectively the medicine is working at this decided dose.

Phase III – In r phase 3 studies, the trial is conducted on a relatively larger number of patients which ranging up to thousands of patients. Both safety and efficacy of the drug is evaluated. Phase IV – Phase 4 is also known as post marketing surveillance. This is done after the drug has been launched in the market. The studies monitor if there are any long-term side effects or study the results in any particular group of the population that weren’t included before.

The clinical trial company makes sure that every phase is conducted with utmost care and accuracy to ensure that the trial results are unbiased and effective.